David, spatialreference.org uses a local SRID with a prepended '9' while maintaining an auth_srid to match EPSG so as not to step on the toes of the SRIDs that are already in the spatial_ref_sys table. While a bit ugly, this is the intended behavior. It uses the '9' because there are no EPSG codes that begin with a 9 so it is a clear namespace to not overwrite an EPSG code regardless of what local SRID identifier is given at spatialreference.org.
Clear as mud? David On Wed, Sep 22, 2010 at 11:41 AM, David Fawcett <david.fawc...@gmail.com>wrote: > A minor issue here, but I am looking for some clarification. > > I am seeking the correct PostGIS srid for UTM Z15N NAD83. > > If I query spatialreference.org, > (http://spatialreference.org/ref/epsg/26915/postgis/) I get: > > INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, > srtext) values ( 926915, 'epsg', 26915, '+proj=utm +zone=15 > +ellps=GRS80 +datum=NAD83 +units=m +no_defs ', 'PROJCS["NAD83 / UTM > zone 15N",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS > > 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4269"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",-93],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],AUTHORITY["EPSG","26915"],AXIS["Easting",EAST],AXIS["Northing",NORTH]]'); > > > From a fairly recent of PostGIS, > > SELECT srid, auth_name, auth_srid > FROM public.spatial_ref_sys > WHERE auth_srid = 26915 > > > I get: 26915 | EPSG | 26915 > > > I am assuming that the definition at spatial ref.org is wrong? > > David. > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users > -- ************************************ David William Bitner
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